Protection of multiple-telegraph instruments.



No; 677,5!9. Pa tented July 2, 19m. F. w. JONES;

PROTECTION OF MULTIPLE TELEGRAPH INSTRUMENTS.

(Application filed Feb, 13, 189B.)

(No Model.)

WITNESSES: INVENTOR koruxba TME Nonms PETERS Puo'wuwc WASHINGTON, o c.

Nrrsn States FRANCIS W. JONES, OF NEW YORK, N. Y.

SPEGIEJEGATION forming part of Letters Eatent No. 677,519, dated July 2,1901. Application filed February 13, 1899. Serial No. 705,394. N model-lTo all whom it may concern:

Be it known that I, FRANCIS W. JONES, a citizen of the United States,residing in the city, county, and State of New York, have made certainnew and useful Improvements in the Protection of Multiple-TelegraphInstruments from Lightning, of which the following is a specification.

M ultiple-telegraph instru ments, such as relays, have two parallelwindings ot' fine silkinsulated wire. One winding is connected into anartificial line and the other winding into the natural line. These twocircuits have substantially the same resistance and capacity. Adischarge of atmospheric electricity results from a disturbance in theatmosphere producing a corresponding disturbance in the electricalcondition of the earths surface.

My improvement provides a lightning-arrester located at a neutral pointas regards the transmitted currents and permits adegree of separationbetween line and ground plates absolutely impracticable in anyarrangement heretofore known, while at the same time the instruments arethoroughly protected by a sensitive arrester and operate in the natureof choke-coils to retard the inflowing atmospheric discharge.

The accompanying drawings illustrate my invention.

Figure l is a complete view of the lightningarrester connected inposition between the main and artificial lines. Fig. 2 is a crosssection of the lightning-arrester, showing the relative position of thevarious parts.

L is the main line.

A is an artificial line, and R an adjustable resistance.

0 is a condenser.

By the use of'R and G the artificial line A is given the same resistanceand capacity possessed by the natural line L.

N is a neutral relay. P is a polarized relay. Both relays have separatecoil-windings upon a single core. A discharge of atmospheric electricitywill break down the insulation between adjacent coil-sections anddestroy the instrument.

cis an induction-coilhaving three windings, one in the line L, one inthe line A, and one in the circuit 19 20 with the extra coil m of therelay N. The function of this coil in diplex telegraphy is to bridge theinterval of no magnetism during reversals. The transmitting-dynamo isconnected to the point T.

Let us assume that it has four hundred volts electromotive force. Whenthis potential is directed to the line, corresponding points in the lineL and A outside the instruments described have the same potential andpolarity.

The lightning-arrester employed by me consists of a base 13 of vitreousinsulating material. Upon its surface there are brass plates 12 and (1.Located centrally between these plates is a post g, connected with theearth by a ground-wireG. The plate 19 is connected to the natural line Lby the wire 9. The plate q is connected to a corresponding point in theline A by the wire -l0.

o is a brass plate fixed to the vitreous cover D. It is centrallyperforated to closely surround the post g. Between the plates 0 and p qis a sheet of isinglass I, having a series of perforations h. I isextremely thin-say three one-thousandths of an inch.

The connection of the two condu'c'tingsurfaces 29 and q to the main andartificial lines, respectively, permits the use of a thinner dielectricor sheet of insulating material I between the two line-plates and thegrounded surface than would be the case were the plate q connected tothe artificial line not present. It has always been necessary to employa thicker sheet of insulating material in the position of the sheet ofmica 1 than was de sirable, because of the high potential of theoutgoing dynamo-current, usually four hundred volts or more. The use ofa thinner sheet I therefore protects the instruments from atone or morereceiving instruments equipped with two coil-sections each, a main line,an artificial line, a lightning-arrester having two separate parallelplates. or connections, a grounded contact-plate equidistant withrespect to the first-named plates or connections and an electricalconnection between the firstnamed plates and points of equal potentialin the main and artificial lines, respectively.

FRANCIS W. JONES. \Vitnesses:

WALTER A. HOUGHTALING, ARTHUR H. BROWN.

